package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IUserService userService;
    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Autowired
    private IFollowService followService;

    @Override
    public Result queryBlogById(Long id) {
        //查询blog
        Blog blog = getById(id);
        if(blog==null){
            return Result.fail("笔记不存在！");
        }
        //查询笔记是否被当前用户点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    /**
     * 笔记被当前用户点赞情况
     * @param blog
     */
    private void isBlogLiked(Blog blog) {
        UserDTO user = UserHolder.getUser();
        //未登录用户也可以查主页 但是当前用户为空 无法查询是否被用户点赞
        if(user == null){
            return;
        }
        String key = RedisConstants.BLOG_LIKED_KEY+blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, user.getId().toString());
        blog.setIsLike(score!=null);
    }

    /**
     * 笔记的发布者情况
     * @param blog
     */
    private void queryBlogUser(Blog blog){
        //查询用户
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    /**
     * 当前用户点赞笔记
     * @param id
     * @return
     */
    @Override
    public Result likeBlog(Long id) {
        Long userId = UserHolder.getUser().getId();
        String key = RedisConstants.BLOG_LIKED_KEY+id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if(score == null){
            boolean isSuccess = update().setSql("liked=liked+1").eq("id",id).update();
            if(isSuccess){
                //保存用户到redis的zset集合 存入用户id和时间戳
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
                return Result.ok("点赞成功");
            }
            return Result.fail("点赞失败");
        }else {
            //已点赞
            boolean isSuccess = update().setSql("liked=liked-1").eq("id",id).update();
            if(isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
                return Result.ok("取消点赞成功");
            }
            return Result.fail("取消点赞失败");
        }
    }

    @Override
    public Result queryBlogLikes(Long id) {
        // 查询top5点赞用户 zrange 0 4
        String key = RedisConstants.BLOG_LIKED_KEY+id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5==null||top5.isEmpty()){
            return Result.fail("点赞榜为空");
        }
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        // 解析出用户id 注意传进的id顺序和结果用户顺序要一致！
        String idStr = StrUtil.join(",", ids);
        List<UserDTO> userDTOList = userService.query().in("id",ids)
                .last("ORDER BY FIELD(id,"+idStr+")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return Result.ok(userDTOList);
    }

    @Override
    public Result saveBlog(Blog blog) {
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        //保存探店笔记
        boolean isSucess = save(blog);
        if(!isSucess){
            return Result.fail("新增笔记失败");
        }
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        for (Follow follow : follows) {
            //获取粉丝id
            Long userId = follow.getUserId();
            //推送消息
            String key = RedisConstants.FEED_KEY+userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        return Result.ok(blog.getId());
    }

    /**
     * 滚动分页查询关注人的笔记
     * @param max 上一次浏览到的最小时间戳 标记此次查询从哪个时间戳开始向前查找
     * @param offset max对应的笔记数量 标记此次查询从max时间戳向前offset单位的位置为真正开始查找的位置
     * @return
     */
    @Override
    public Result queryBlogofFollow(Long max, Integer offset) {
        //找到收件箱
        Long userId = UserHolder.getUser().getId();
        String key = RedisConstants.FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        if(typedTuples==null||typedTuples.isEmpty()){
            return Result.ok();
        }
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            ids.add(Long.valueOf(typedTuple.getValue()));
            long time = typedTuple.getScore().longValue();
            if(time == minTime){
                os++;
            }else {
                minTime = time;
                os = 1;
            }
        }
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Blog blog : blogs) {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        }
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setMinTime(minTime);
        scrollResult.setOffset(os);
        return Result.ok(scrollResult);
    }
}
